Network Reliability and Resilience

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Network Reliability and Resilience

• Mark S. Daskin
• Dept. of IE/MS
• Northwestern University

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Reliability and Resilience

• Reliability
• Low probability of failure

• Resilience
• Consequences of failure are designed to be small
• Return to normal function is rapid

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Outline

• Framework for network resilience
• Industry perspectives
• Examples of research at NU
• Directions for future work and collaboration

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Sources of Supply Chain or Network Unreliability

• Natural disasters
• Weather
• Congestion of facilities
• Business failures
• Economics, Energy,Environment
• Labor disruptions
• Terrorist actions

Decreasingly random in nature

• Different
• Durations
• Targets
• Responses

We live in an uncertain world.
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Reliability/Resilience TaxonomyFrequency/Severit
y
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Reliability/Resilience TaxonomyDuration is also
important
Frequency how often does something
fail Severity what fraction of network
capability is lost what is the cost?
Duration how long is it disabled
Severity
Duration
Frequency
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Threats and countermeasures
Lobbying
Regulation/other
RD/new prod.
Forecasting
Multi-sourcing
Firm
Firm
Firm
Fortification
Inventory
Market res.
Contracts/flex.
RD/options
Inv./options
Purchase options
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Threats and countermeasures
Multi-sourcing
Fortification/ Intelligence/ Detection
Firm
Firm
Firm
Inventory
Yield high frequency, short duration, low
consequence, unpredictable Supplier reliability
lower frequency, longer duration, moderate
consequence, may be targeted Terrorism very
low frequency, long duration, high consequence,
targeted
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Threats and countermeasures
Recovery plans
Firm
Firm
Airline
Fortification
Inducements
Overbooking high frequency, few flights
impacted, low consequence, somewhat
unpredictable Weather delay lower frequency,
longer duration, moderate to high network
consequences, may be foreseen Terrorism very
low frequency, very long duration, high
consequence, targeted at vulnerable facilities
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Event planning is a cycle
Pre-event
Post event
During event
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Pre-event planning

• Prevent events
• Defend against events (harden facilities)
• Design systems to be resilient with respect to
  failures

• Prevent overbooking via improved forecasting
• Defend against terrorism via screening
• Design routes and networks to be robust w.r.t.
  weather delays

• Prevent shortages thru better forecasting
• Defend against shortages via safety stock
• Design products for substitutabilitynetworks
  with multiple suppliers

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During event

• Detect events
• Diagnose event
• Prescribe action
• Communicate action
• Coordinate response
• Control response

• Detect weather problems early
• Diagnose severity of disruption due to weather
• Prescribe response (reroute aircraft, call in
  backup crews)
• Communicate passengers
• Coordinate with other airlines and hotels
• Control entire response

• Detect shortages by monitoring key suppliers
• Diagnose shortage severity (total, partial)
• Prescribe actions (draw on safety stock, invoke
  contracts)
• Communicate plans with plants, suppliers, and
  customers
• Coordinate response across system
• Control production

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Post event

• Recovery actions
• Redesign system for better response
• Reconstruct system

• Recovery actions to reposition aircraft and crews
• Redesign network, routes, aircraft assignments,
  response system
• Reconstruct may not be applicable in weather case
  except in the extreme

• Recovery actions to get production back and
  marketing to recover market share
• Redesign supply chain to mitigate future
  shortages (improve forecasting, safety stock,
  multi-source)
• Reconstruct supply chain and replenish safety
  stocks

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Key observations

• Network effects make pre-event, during event and
  post-event difficult
• Solutions must encompass
• Detection and Diagnosis
• Communication and Coordination
• Recovery and Redesign

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Questions for Industry

• How do you think about resilience?
• How do you ensure resilience?
• How do you monitor your network(s)?
• What is the impact of a network failure?
• How do you contain/recover from failures?
• What unmet needs do you have?